Air filter



FIG. 1 is a front perspective view from the right side of the air filter, according to the claimed design;

FIG. 2 is a front view of the air filter of FIG. 1;

FIG. 3 is a rear view of the air filter of FIG. 1;

FIG. 4 is a left side view of the air filter of FIG. 1;

FIG. 5 is a right side view of the air filter of FIG. 1;

FIG. 6 is a top view of the air filter of FIG. 1;

FIG. 7 is a bottom view of the air filter of FIG. 1; and,

FIG. 8 is a cross-section view of the air filter of FIG. 1 along line 8-8 of FIG. 2. 

CLAIM We claim the ornamental design for an air filter, as shown and described. 